Currently, the shield-to-shield separation of a spin valve head cannot be below about 800 Å, mainly due to sensor-to-lead shorting problems. This problem has now been overcome by inserting a high permeability, high resistivity, thin film shield on the top or bottom (or both) sides of the spin valve sensor. A permeability greater than about 500 is required together with a resistivity about 5 times greater than that of the free layer and an MrT value for the thin film shield that is 4 times greater than that of the free layer. Five embodiments of the invention are described.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A top spin valve structure, comprising: on a first dielectric layer, a layer of magnetic material suitable for use as a free layer in said spin valve; on the free layer, a layer of non-magnetic material; on the layer of non-magnetic material, a layer of magnetic material suitable for use as a pinned layer in said spin valve; on the pinned layer, a layer of an anti-ferromagnetic material suitable for use as a pinning layer in said spin valve; on the anti-ferromagnetic layer, a layer of material suitable for use as a decoupling layer; and on the decoupling layer, a thin film shield that further comprises a layer of high permeability ferromagnetic material, said material having an electrical resistivity greater than about 125 micro-ohm-cm and a thickness such that the product of its moment and thickness is 2 to 5 times that of the free layer; a trench that extends through the thin film shield as far as said first dielectric layer, said trench having a sidewall that slopes; on the first dielectric layer and on the sidewall, a layer of a ferromagnetic material suitable for use as a permanent magnet for providing longitudinal bias to the structure; on the permanent magnet layer, a layer of conductive material suitable for use as a connecting lead to the structure; and on the thin film shield and on the conductive lead layer, a second dielectric layer.
2. The structure described in claim 1 wherein the thin film shield is selected from the group consisting of nickel-iron-chromium, cobalt-niobium-zirconium, cobalt-niobium-hafnium, iron-cobalt-nitrogen, iron-cobalt-chromium, iron-cobalt-tantalum, and iron-cobalt-titanium and has a permeability greater than about 500.
3. A top spin valve structure, including a free layer, comprising: on a first dielectric layer, a thin film shield that further comprises a layer of high permeability ferromagnetic material, said material having an electrical resistivity greater than about 125 micro-ohm-cm and a thickness such that the product of its moment and thickness is 2 to 5 times that of the free layer; on the thin film shield, a layer of material suitable for use as a decoupling layer; on said decoupling layer, a layer of magnetic material suitable for use as the free layer in said spin valve; on the free layer a layer of non-magnetic material; on the layer of non-magnetic material, a layer of magnetic material suitable for use as a pinned layer in said spin valve; on the pinned layer, a layer of an anti-ferromagnetic material suitable for use as a pinning layer in said spin valve; a trench that extends through the anti-ferromagnetic layer as far as said first dielectric layer, said trench having a sidewall that slopes; on the first dielectric layer and on the sidewall, a layer of a ferromagnetic material suitable for use as a permanent magnet for providing longitudinal bias to the structure; on the permanent magnet layer, a layer of conductive material suitable for use as a connecting lead to the structure; and on the anti-ferromagnetic layer and on the conductive lead layer, a second dielectric layer.
4. The structure described in claim 3 wherein the thin film shield is selected from the group consisting of nickel-iron-chromium, cobalt-niobium-zirconium, cobalt-niobium-hafnium, iron-cobalt-nitrogen, iron-cobalt-chromium, iron-cobalt-tantalum, and iron-cobalt-titanium and has a permeability greater than about 500.
5. A top spin valve structure, comprising: on part of a first dielectric layer, a layer of conductive material suitable for use as a connecting lead to the structure; on the conductive lead material, a layer of a ferromagnetic material suitable for use as an exchange magnet for providing longitudinal bias to the structure; on said first dielectric layer and on the exchange magnet layer, a layer of magnetic material suitable for use as a free layer in said spin valve; on the free layer, a layer of non-magnetic material; on the layer of non-magnetic material, a layer of magnetic material suitable for use as a pinned layer in said spin valve; on the pinned layer, a layer of an anti-ferromagnetic material suitable for use as a pinning layer in said spin valve; on the anti-ferromagnetic layer, a layer of material suitable for use as a decoupling layer; on the decoupling layer, a thin film shield that further comprises a layer of high permeability ferromagnetic material, said material having an electrical resistivity greater than about 125 micro-ohm-cm and a thickness such that the product of its moment and thickness is 2 to 5 times that of the free layer; and on the thin film shield, a second dielectric layer.
6. The structure described in claim 5 wherein the thin film shield is selected from the group consisting of nickel-iron-chromium, cobalt-niobium-zirconium, cobalt-niobium-hafnium, iron-cobalt-nitrogen, iron-cobalt-chromium, iron-cobalt-tantalum, and iron-cobalt-titanium and has a permeability greater than about 500.
7. A bottom spin valve structure, including a free layer, comprising: on a first dielectric layer, thin film shield that further comprises a layer of high permeability ferromagnetic material, said material having an electrical resistivity greater than about 125 micro-ohm-cm and a thickness such that the product of its moment and thickness is 2 to 5 times that of the free layer; on the thin film shield, a layer of material suitable for use as a decoupling layer; on the decoupling layer, a layer of an anti-ferromagnetic material suitable for use as a pinning layer in said spin valve; on the anti-ferromagnetic layer, a layer of magnetic material suitable for use as a pinned layer in said spin valve; on the pinned layer, a layer of non-magnetic material; on said pinned layer, a layer of magnetic material suitable for use as a free layer in said spin valve; a shallow trench that extends part way through the free layer, said trench having a sidewall that slopes; on the free layer outside the trench, a capping layer selected from the group consisting of tantalum, tantalum oxide, and alumina; on the free layer inside the trench, a layer of material that is the same as that of the free layer; on the capping layer, a layer of a ferromagnetic material suitable for use as an exchange magnet for providing longitudinal bias to the structure; on the exchange magnet layer, a layer of conductive material suitable for use in connecting leads to the structure; on the conducting lead layer, a second dielectric layer.
8. The structure described in claim 7 wherein the thin film shield is selected from the group consisting of nickel-iron-chromium, cobalt-niobium-zirconium, cobalt-niobium-hafnium, iron-cobalt-nitrogen, iron-cobalt-chromium, iron-cobalt-tantalum, and iron-cobalt-titanium and has a permeability greater than about 500.
9. A double shielded top spin valve structure, including a free layer, comprising: providing a lower primary magnetic shield on which is a first dielectric layer; on a first dielectric layer, a first thin film shield that further comprises a first layer of high permeability ferromagnetic material, said material having an electrical resistivity greater than about 125 micro-ohm-cm and a thickness such that the product of its moment and thickness is 2 to 5 times that of the free layer; on the first thin film shield, a layer of material suitable for use as a first decoupling layer; on said first decoupling layer, a layer of magnetic material suitable for use as a free layer in said spin valve; on the free layer, a layer of non-magnetic material; on the layer of non-magnetic material, a layer of magnetic material suitable for use as a pinned layer in said spin valve; on the pinned layer, a layer of an anti-ferromagnetic material suitable for use as a pinning layer in said spin valve; on the anti-ferromagnetic layer, a layer of material suitable for use as a second decoupling layer; and on the second decoupling layer, a second thin film shield that further comprises a second layer of high permeability ferromagnetic material, said material having an electrical resistivity greater than about 125 micro-ohm-cm and a thickness such that the product of its moment and thickness is 2 to 5 times that of the free layer; a trench that extends through the second thin film shield as far as said first dielectric layer, said trench having a sidewall that slopes; on the first dielectric layer and on the sidewall, a layer of a ferromagnetic material suitable for use as a permanent magnet for providing longitudinal bias to the structure; on the permanent magnet layer a layer of conductive material suitable for use as a connecting lead to the structure; and on the second thin film shield and on the conductive lead layer, a second dielectric layer.
10. The structure described in claim 9 wherein the thin film shields are selected from the group consisting of nickel-iron-chromium, cobalt-niobium-zirconium, cobalt-niobium-hafnium, iron-cobalt-nitrogen, iron-cobalt-chromium, iron-cobalt-tantalum, and iron-cobalt-titanium and has a permeability greater than about 500.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
December 14, 2004
February 7, 2006
Browse 5M+ US patents with plain-English claim translations and AI-generated analysis.